(a) Technical Field
The present invention relates to a thin film transistor array panel and a manufacturing method thereof.
(b) Discussion of the Related Art
A thin film transistor (TFT) array panel may be used as a circuit board for independently driving pixels in a liquid crystal display or an organic electro-luminescent (EL) display device. A thin film transistor array panel typically includes a scanning signal line or a gate line transmitting a scanning signal, an image signal line or a data line transmitting an image signal, a thin film-transistor connected to the gate line and the data line, and a pixel electrode connected to the thin film transistor.
A thin film transistor typically includes a gate electrode formed on the gate wire, a source electrode formed on the data wire, a drain electrode, and a channel formed in a semiconductor layer between the source and drain electrodes. The thin film transistor is essentially a switching element that controls an image signal transmitted to the pixel electrode through the data wire in response to the scanning signal transmitted through the gate line.
In order to reduce the manufacturing time and cost during fabrication of a thin film transistor array panel, the number of fabrication processing steps using a mask can be reduced. For example, a four mask process for forming the data line and the semiconductor layer may be completed using only one mask. In the four mask process, when defects occur during the formation of a photosensitive film pattern, the defective photosensitive film pattern is removed and a new photosensitive film pattern is formed. The repeated formation of a photosensitive film pattern on the data line, may comprise copper or a copper alloy, may result in damage to the data line. For example, the data line may be easily disconnected at a portion where the data line has a step. In addition, wet etching steps used during the four mask process further increase the possibility of the data line becoming disconnected during manufacture.